Well finally we have our new addition, over the last week we've had our new baby Bengal 12 weeks old in his safe room, slowly he is getting used to all other family members and is exploring out side the boundaries of his safe room, problem I have is my other 2 yo cat, domestic long hair, he will growl and hiss at sir Lancelot non stop, he is making really aggressive noises and I feel they might never get along, any ideas to bring 2yo into line?

I don't have any experience of this, but I will say that it might take longer for them to get along than a week. We've had our kitten for 3 weeks and I have seen quite a big change over the last week. We have a dog that is 7 and all of a sudden I feel like they've just clicked!

Try not to stress and rush into wanting them to get along and just give them time and space.

I'm sure it will work out. Good luck!

A few comments/suggestions:

1. Do a forum search on "introduction" and you'll see many many many many posts asking this same thing. Then ask specific questions.
2. Whenever you introduce a new cat to a happy adult cat, you run the risk of that adult cat getting cheesed off. You are right in that there is a chance that they may never get along. But it is way way too soon to reach such a conclusion, and it sounds like you really haven't put in the effort that you will probably have to, to make it work.
3. If you are interested in understanding what might be going on with your cats, there is a really good book called "cat vs cat" that gives quite a bit of insight and suggestions.
4. I think it's really backwards to be looking at the problem as "bringing the 2yo into line". That shouldn't be the goal. The goal should be to have 2 happy cats, which roughly translates into you appeasing first the 2yo, then the kitten in that order, especially since you are the instigator of this problem.

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The little monsters 3

2yo ( Sylvester ) body language is very neutral, he will lay down at the doors entrance just looking at Lancelot, his tail not swaying from side to side, no arched back or hair standing up, he looks generally interested in his play time, when Lancelot gets within 5-6 feet the hissing growling and snorting will take place, or if Lancelot even looks at Sylvester he will hiss, Sylvester will play with his toys if encouraged to do so, I does seem he's pulling himself "into line" :)
Although a little way away from being trusted by themselves.

It takes a while in most cases. A stranger has popped into your lives and with other cats, it takes some getting used to. I'm sure they hiss at the new member in the hopes of "scaring" them off. LOL. Seriously .... it just takes some time.

http://www.youtube.com/watch?v=H_mgXHAMDZI

watch this series, it's got really good info on cat body language and introductions. Good luck, you need time, patience and persistence.

I agree, time will make a huge difference!

Your new kitten is an intruder to your 2 year old cat, they are not just going to be accepted straight away. Your 2 year old may or may not accept your new kitten. They may become best friends over time or may just tolerate one another and stay out of each other's way. Time will tell though but you are definitely giving them the best chance to establish a relationship in keeping your new kitten in a safe room. As long as you go through the introduction process slowly and step by step, you will give your cats the best chance at establishing the happy and healthy relationship you wish for them to have.

Good luck and let us all know how you progress

Update- Lancelot and Sylvester are now touching noses, lance has well and truely come out of his shell and now rules the house, Sylvester has given up his sleeping spot to lance, he will still hiss now and again but seems he will put up with lance now.
Lance is very cheeky and will sneak up on Sylvester while he's eating and tap him, again Sylvester will put up with this and even gives up his food.
Seems Bengals have the balls to take it to much bigger cats as Sylvester is a rather large cat.

My Bengal (8.5 lb. girl) whipped my 18+ lb. beast of a male cat into shape in about a month! So much to the point that he lost three pounds! But he loves her and is so happy to have a friend to wrestle with now. It is funny how that works out sometimes, isn't it!

Looks like one is a tree dweller one is a bush dweller!